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Much improved row move implementation

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This commit is contained in:
Keith Edmunds 2025-04-16 10:23:44 +01:00
parent bf5563f2f1
commit 6fb6339843
2 changed files with 125 additions and 63 deletions
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176
app/ds.py
View File

@ -472,6 +472,8 @@ def _playlist_check_playlist(
else raise ApplicationError.
"""
fixed = False
playlist_rows = (
session.execute(
select(PlaylistRows)
@ -492,9 +494,13 @@ def _playlist_check_playlist(
if fix:
log.debug(msg)
plr.row_number = idx
fixed = True
else:
raise ApplicationError(msg)
if fixed:
session.commit()
# @log_call
def _playlist_shift_rows(
@ -696,88 +702,145 @@ def playlist_move_rows(
to_playlist_id: int | None = None,
) -> None:
"""
Move rows with or between playlists.
Call helper function depending upon whether we are moving rows within
a playlist or between playlists.
"""
# If to_playlist_id isn't specified, we're moving within the one
# playlist.
if to_playlist_id is None or to_playlist_id == from_playlist_id:
_playlist_move_rows_within_playlist(from_rows, from_playlist_id, to_row)
else:
_playlist_move_rows_between_playlists(
from_rows, from_playlist_id, to_row, to_playlist_id
)
def _playlist_move_rows_between_playlists(
from_rows: list[int],
from_playlist_id: int,
to_row: int,
to_playlist_id: int,
) -> None:
"""
Move rows between playlists.
Algorithm:
- Sanity check row numbers
- Check there are no playlist rows with playlist_id == PENDING_MOVE
- Put rows to be moved into PENDING_MOVE playlist
- Resequence remaining row numbers
- Make space for moved rows
- Move the PENDING_MOVE rows back and fixup row numbers
- Sanity check row numbers
"""
# If to_playlist_id isn't specified, we're moving within the one
# playlist.
if to_playlist_id is None:
to_playlist_id = from_playlist_id
# Sanity check destination not being moved
if to_row in from_rows:
log.error(
f"ds._playlist_move_rows_within_playlist: {to_row=} in {from_rows=}"
)
return
with db.Session() as session:
# Sanity check row numbers
_playlist_check_playlist(session, from_playlist_id, fix=False)
if from_playlist_id != to_playlist_id:
_playlist_check_playlist(session, to_playlist_id, fix=False)
_playlist_check_playlist(session, to_playlist_id, fix=False)
# Check there are no playlist rows with playlist_id == PENDING_MOVE
pending_move_rows = playlistrows_by_playlist(Config.PLAYLIST_PENDING_MOVE)
if pending_move_rows:
raise ApplicationError(f"move_rows_to_playlist: {pending_move_rows=}")
# Make space in destination playlist
_playlist_shift_rows(session, to_playlist_id, to_row, len(from_rows))
# We need playlist length if we're moving within a playlist. Get
# that now before we remove rows.
from_playlist_length = len(playlistrows_by_playlist(from_playlist_id))
# Put rows to be moved into PENDING_MOVE playlist
session.execute(
update(PlaylistRows)
.where(
PlaylistRows.playlist_id == from_playlist_id,
PlaylistRows.row_number.in_(from_rows),
)
.values(playlist_id=Config.PLAYLIST_PENDING_MOVE)
)
# Resequence remaining row numbers
_playlist_check_playlist(session, from_playlist_id, fix=True)
session.commit()
# Make space for moved rows. If moving within one playlist,
# determning where to make the space is non-trivial. For example,
# if the playlist has ten entries and we're moving four of them
# to row 8, after we've moved the rows to the
# PLAYLIST_PENDING_MOVE there will only be six entries left.
# Clearly we can't make space at row 8...
space_row = to_row
if to_playlist_id == from_playlist_id:
overflow = max(to_row + len(from_rows) - from_playlist_length, 0)
if overflow != 0:
space_row = (
to_row - overflow - len([a for a in from_rows if a > to_row])
)
_playlist_shift_rows(session, to_playlist_id, space_row, len(from_rows))
# Move the PENDING_MOVE rows back and fixup row numbers
# Update database
# Build a dictionary of changes to make
update_list: list[dict[str, int]] = []
next_row = space_row
# PLAYLIST_PENDING_MOVE may have gaps so don't check it
for row_to_move in playlistrows_by_playlist(
Config.PLAYLIST_PENDING_MOVE, check_playlist_itegrity=False
):
old_row_to_id = _playlist_rows_to_id(from_playlist_id)
next_row = to_row
for from_row in from_rows:
plrid = old_row_to_id[from_row]
update_list.append(
{"id": row_to_move.playlistrow_id, "row_number": next_row}
{"id": plrid, "row_number": next_row}
)
update_list.append(
{"id": row_to_move.playlistrow_id, "playlist_id": to_playlist_id}
{"id": plrid, "playlist_id": to_playlist_id}
)
next_row += 1
session.execute(update(PlaylistRows), update_list)
session.commit()
# Resequence row numbers in source
_playlist_check_playlist(session, from_playlist_id, fix=True)
# Sanity check destionation
_playlist_check_playlist(session, from_playlist_id, fix=False)
def _playlist_rows_to_id(playlist_id: int) -> dict[int, int]:
"""
Return a dict of {row_number: playlistrow_id} for passed playlist
"""
row_to_id = {
p.row_number: p.playlistrow_id
for p in playlistrows_by_playlist(playlist_id)
}
return row_to_id
# @log_call
def _playlist_move_rows_within_playlist(
from_rows: list[int],
from_playlist_id: int,
to_row: int,
) -> None:
"""
Move rows within playlists.
Algorithm:
- Sanity checks
- Create a list of row numbers in the new order
- Update the database with the new order
- Sanity check row numbers
"""
# Sanity check destination not being moved
if to_row in from_rows:
log.error(
f"ds._playlist_move_rows_within_playlist: {to_row=} in {from_rows=}"
)
return
with db.Session() as session:
# Sanity check row numbers
_playlist_check_playlist(session, from_playlist_id, fix=False)
# Create a list showing the new order of rows in playlist
# Start with a list of rows excluding those to be moved
from_playlist_length = len(playlistrows_by_playlist(from_playlist_id))
new_row_order = [a for a in range(from_playlist_length) if a not in from_rows]
# Insert the moved row numbers
try:
idx = new_row_order.index(to_row)
except ValueError:
raise ApplicationError(f"Can't find {to_row=} in {new_row_order=}")
new_row_order[idx:idx] = from_rows
# Update database
# Build a dictionary of {old_row_number: new_row_number} where
# they differ
row_changes = {old: new for new, old in enumerate(new_row_order) if old != new}
# Build a dictionary of changes to make
update_list: list[dict[str, int]] = []
old_row_to_id = _playlist_rows_to_id(from_playlist_id)
for old_row, new_row in row_changes.items():
plrid = old_row_to_id[old_row]
update_list.append({"id": plrid, "row_number": new_row})
# Updte database
session.execute(update(PlaylistRows), update_list)
session.commit()
# Sanity check row numbers
_playlist_check_playlist(session, from_playlist_id, fix=False)
if from_playlist_id != to_playlist_id:
_playlist_check_playlist(session, to_playlist_id, fix=False)
def playlists_open() -> list[PlaylistDTO]:
@ -905,7 +968,6 @@ def playlist_remove_rows(playlist_id: int, row_numbers: list[int]) -> None:
)
# Fixup row number to remove gaps
_playlist_check_playlist(session, playlist_id, fix=True)
session.commit()
# @log_call

12
tests/test_ds.py
View File

@ -165,7 +165,7 @@ class MyTestCase(unittest.TestCase):
new_order = []
for row in ds.playlistrows_by_playlist(playlist.playlist_id):
new_order.append(int(row.note))
assert new_order == [0, 1, 2, 4, 5, 3, 6, 7, 8, 9]
assert new_order == [0, 1, 2, 4, 3, 5, 6, 7, 8, 9]
def test_move_rows_test2(self):
# move row 4 to row 3
@ -207,7 +207,7 @@ class MyTestCase(unittest.TestCase):
new_order = []
for row in ds.playlistrows_by_playlist(playlist.playlist_id):
new_order.append(int(row.note))
assert new_order == [0, 2, 3, 6, 7, 8, 1, 4, 5, 10, 9]
assert new_order == [0, 2, 3, 6, 7, 1, 4, 5, 10, 8, 9]
def test_move_rows_test5(self):
# move rows [3, 6] → 5
@ -221,7 +221,7 @@ class MyTestCase(unittest.TestCase):
new_order = []
for row in ds.playlistrows_by_playlist(playlist.playlist_id):
new_order.append(int(row.note))
assert new_order == [0, 1, 2, 4, 5, 3, 6, 7, 8, 9, 10]
assert new_order == [0, 1, 2, 4, 3, 6, 5, 7, 8, 9, 10]
def test_move_rows_test6(self):
# move rows [3, 5, 6] → 8
@ -235,7 +235,7 @@ class MyTestCase(unittest.TestCase):
new_order = []
for row in ds.playlistrows_by_playlist(playlist.playlist_id):
new_order.append(int(row.note))
assert new_order == [0, 1, 2, 4, 7, 8, 9, 10, 3, 5, 6]
assert new_order == [0, 1, 2, 4, 7, 3, 5, 6, 8, 9, 10]
def test_move_rows_test7(self):
# move rows [7, 8, 10] → 5
@ -258,13 +258,13 @@ class MyTestCase(unittest.TestCase):
number_of_rows = 11
(playlist, model) = self.create_rows("test_move_rows_test8", number_of_rows)
ds.playlist_move_rows([0, 1, 2, 3], playlist.playlist_id, 0)
ds.playlist_move_rows([1, 2, 3], playlist.playlist_id, 0)
# Check we have all rows and plr_rownums are correct
new_order = []
for row in ds.playlistrows_by_playlist(playlist.playlist_id):
new_order.append(int(row.note))
assert new_order == [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
assert new_order == [1, 2, 3, 0, 4, 5, 6, 7, 8, 9, 10]
def test_move_rows_to_playlist(self):
number_of_rows = 11